Etching machine



Nov. 26, 1929. F. r. POWERS ETCHING MACHINE Filed Sept. 15.1926

INVENTOR 1 1 One object of my invention is to enable the Figure I is a general assembled view of the 60 ing process to alter the position of the plate the spraying device.

20, of etching apparatus now in use. spray producing unit. 7

Patented Nov. 26, 1929 i v 'VVITUNITED STATES PATENT OFFICE ETGI-IING MACHINE Application filed September 15, 1926. Serial No. 135,696.

The invention relates to improvements in teristics, such as fineness of particles, volume apparatus intended for use in the preparation of fluid sprayed and velocity of travel of the of the surfaces of metal plates used in printparticles. ing by the chemical action thereon of an The various novel features of my inven- 5 etching fluid. Apparatus of this character tion will be more fully set forth and illusis useful in certain stages of the preparation trated in the accompanying description and ,of photo-mechanical printing plates known drawings. as half-tone plates? or line cuts, and for In the drawings like numbers are used to other purposes. indicate the same or similar parts.

operator to etch a printing plate at one 0011- apparatus with portions indicated as cut tinuous operation for each stage or bite, as away to give a clearer view of interior. eleit is called, of the etching process without the ments.

necessity of stopping or interrupting the etch- Figure II shows a side view of one form of or to remove from its surface, by means of a Figure III shows an end view of the device I brush or otherwise, the oxide or residue left shown in Figure II.

on the plate by the etching process, which it Figure IV is a side view, in perspective, of

I is commonly necessary to do with other forms one special form of plate or element for the Another object of my invention is to pro- Referring more in detail to the drawings vide means for producing an etching action in Figure I, 1 indicates an acid-proof liquid of such uniformity over the entire surface of V receptacle, within which is suitably mounted the plate that what the printer calls color a rotating spraying device 2 fixed to a shaft values in the half-tones and shadows will be 3. Suitable means, not shown in the drawtruly retained and at the same time give such ing, are provided for rotating shaft 3 at suitample depth of etching of the plate as will ablespeed or at various speeds. On the unyield satisfactory printing quality. derslde of the cover 1 of the receptacle 1 are It is also important that the etching proprovided means for holding the plate 5 or 30 gress vertically down the sides of the lines or other object to be etched. In the drawing 0 dots perpendicular to the surface of the plate slotted cleats 6, 6 are shown for the convenient withoutundercutting or shouldering. These reception of plates to be etched, but these highly desirable results are attained by my means may be varied to suit the form and invention to a degree far in excess of those size of article to be etched. On one side of .35 produced by machines heretofore in use for the interior of the receptacle, the side opthis purpose. posite tothat near which the rotating mem- Another advantage possessed by this inher 2 is mounted, is provided a ledge 7 or vention over other forms of etchers using equivalentsupport upon which may be placed rotating sprayers lies in the fact that with a a plate 8 to be etche I 40 sprayer of the form described the plate may In Figure II, which shows a side view of be etched, either in a substantially horizontal the rotating member, 9 indicates plates or eleposition, face downward, attached to the unments of suitable material mounted on a shaft derside of the cover of the machine, or in a 3, with spacers 1O alternating with the plates substantially vertical position in the path of or elements 9. Said spacers being of suitable 45 the spray. This feature enables the operator thickness to hold the said plates ata suitable to etch plates in either position or to etch distance apart on the shaft 3. On either side plates placed in both positions simultaof the aggregation of alternate plates 9 and neously. v spacers 10 are nuts 11 Whose interior threads Still another important advantage is the engage mating threads 12, on the shaft 3, and 59 ability to produce sprays of varying characby means of these nuts the plates and spacers are held firmly together on the shaft. A spline or key 13 engaging both the shaft and the plates and spacers, prevents the plates and spacers from rotating on the shaft.

It must be understood that there are many possible variations from the form and construction of the apparatus shown in the drawings and thatI do not intend to limit myself to this particular form or design or construction or combination of parts so long as the spirit of the invention is adhered to.

Having described the drawings showing one of the preferred forms of the invention, I

a will now describe the method of its operation.

Before starting the operation liquid receptacle l is filled with a suitable etching fluid to a point below the shaft 3. The level of this etching fluid is such that the corners of the plates or elements 9 of the rotating spraying device 2 will dip into the fluid and pick up on their sides and edges aportion of the liquid while passing through it, only to throw off the liquid by centrifugal force as that portion of the spraying element passes over the top of the shaft and re-enters the liquid on the other side.

The metal plate or'plates to be etched are attached by means of the slots 6 to the under side of the cover t or the plate may be stood up in a nearly vertical position inside the tank leaning against the front of the tank and supported by the ledge 7. This ability to etch two or more plates, one attached to the cover of the apparatus'and at the same time etch one or more plates standing the tank is one of the important advantages of my invention not possessed by other machines now in use for this purpose. Having closed the cover,

the power'is applied to the shaft 3 which results in the rotating elements of the sprayer picking up the etching fluid and throwing it in fine drops against the plates to be etched. While these rotating elements pass through the fluid the corners of elements beat up the liquid and in a very short time produce an aerated fluid or frothy emulsion which is found to be very desirable and eflective as an etching medium. This aerating effect is produced to a marked degree by elements of a rectangular shape or by elements of other than circular form. It has been found that circular or cylindrical elements in this rotating member or sprayer do not produce the much desired results on the plate being etched that elements or sections of polygonal shapes produce.

At the expiration of a definite period of 'timewhich has been predetermined by experimentor experience the power is shut off,

the sprayer comes to a standstill and the finished plates are removed.

It has been found with certain grades of etching amore violent spraying action is advantageous. In order to increase the quantity of etching fluid thrown against the member, also referred to as the'sprayer, is deused instead of the form shown in Figures II and III.

Obviously a'greatvariety of forms of vanes or buckets could be devised which would serve the purpose of increasing the amount of etching fluid which the revolving polygonal element will pick up as it revolves in the etching fluid. I do not confine myself to any particular form or design. One advantage possessed by the form of bucket indicated in the drawing lies in the fact that when theelement is rotated in the direction indicated by the arrow, a portion of the etching fluid picked up by the forward outer'tip ofthe vanes or buckets will, by reason of its inertia, flow over the entire inner advancing faces 15 ofthe buckets 14, and pass around and beyond'the inner portion of the bucket between the bucket and the shaft 3, only to be picked up in turn by the succeeding bucket'and projected therefrom, by centrifugal force, against the object to be etched.

In the foregoing description therotating scribed as composed of alternate platesand spacers. This is the preferred construction but I find that variations from this form are while at the same time it throws drops of the fluid forcibly against the surface of the metal plate being etched. I

I am aware that etching machines having "paddle wheels of various forms have been and are 1n use and that in etching machines of this'general character some etch theplate in a horizontal, facedown position and others in a vertical position. I am therefore limiting my claims to those features which I believe to be new and novel.

Having described my invention and its method of operation, I will'now state what I claim to be novel and new upon which I desire to secure Letters Patent:

1. A device for sprayinga fluid comprising a rotatable member composed of thin elements having the form of a rectilinear polygon mounted at spaced distances apart on a shaft.

2. A device for spraying a fluid comprising a rotatable member composed of thin ele ments having the form of a regular rectilinear polygon mounted at spaced distances apart on a shaft.

3. A device for spraying a fluid comprising a rotatable member composed of thin elements having the form of a regular, equilateral rectilinear polygon mounted at spaced distances apart on a shaft.

l. A device for use in an etching machine for spraying the etching fluid, comprisng a rotatable member composed of thin elements having polygonal form mounted at equal distances apart on a shaft.

5. A spraying device for use in an etching machine, comprising a rotatable member composed of thin elements of rectangular form mounted on a shaft.

6. A spraying device for use in an etching machine, comprising a rotatable member composed of a shaft upon Which is mounted elements of polygonal form, having at corners of the elements vanes adapted to dip into, pick up and project the etching fluid.

Signed at Douglaston, in the county of Queens, city and State of New York, this tenth day of September, A. D. 1926.

FRANK T. POWVERS. 

